Burnout is not just “tiredness”. Explaining with biology.

Demid Ost
4 min readMay 23


More and more people working in startups say that they are burnt out. It has become so widespread that it feels trendy nowadays as if working in a high-paced environment, having calls with the U.S. at 9 PM, and drinking coffee 24/7 make you on the crest of a wave.

But what does it actually mean? And why isn’t burnout just being “tired,” but a serious and major problem pandemic in size?

It’s all about mitochondria.

Evolutionarily, our brains are used to physical work. Nowadays, when physical safety is achieved by civilization, most of the work falls on our brain, which is not meant to be used so intensively by nature.

Our energy is stored in our cells, and part of the cells, the mitochondria, are energy keepers, like gas tanks in cars. When there is no fuel in the tank, the car cannot drive. The same happens with our bodies. When you do lift-ups in a gym, you start feeling pain. It means that there is no more energy in mitochondria, and nerve cells send messages to the brain that you should stop.

The same mitochondria are located in our neuron cells. Unfortunately, there is no nerve connection in the brain, and we do not feel pain when we are tired (read: mitochondria are exhausted). That’s the reason why people can be burnt out for years and continue going, and only when the situation is unbearable the burnt-out person asks for help.

For understanding exactly what happens, let’s look into the neuron cell.

To send information to the next neuron, axon terminal cells push neuromediators like dopamine, serotonin and etc. out of the vesicle, the neuron on the other side accepts neuromediators with receptors.

Synaptic cleft when sending a signal between neurons

When vesicles are exhausted, mitochondria create new vesicles that later move to axon terminals. Usually, 8 hours of sleep is enough to restore vesicles with neuromediators. However, if mitochondrias are exhausted, sleep is not enough at all. This means that exhausted mitochondria cannot produce vesicles with neuro mediators.

New vesticles are moving to axon terminals

Serotonin is a neuromediator that is responsible for slowing down brain activity. When there isn’t enough serotonin in the brain, neurons can’t stop working. This constant firing triggers one thought after another, making it difficult for the brain to rest.

Excessive brain activity and stress cause a lack of serotonin in brain cells, which leads to head pains, anxiety, chronic tiredness, emotional fatigue, negative thoughts, low motivation, social distance and even fainting.

That’s why burnout is not just tiredness; it’s a biological problem in the brain and should be treated accordingly. When a person breaks their leg, you don’t tell them to “just relax” and expect them to run a marathon the next day. Similarly, it doesn’t make sense to tell people that they should just rest or stop worrying. The problem is that they can not.

What causes burnout

Now that you know what burnout is, let’s talk about what causes it. Here are some factors that increase the chance of burning out:

  1. Hyperresponsibility. Hyperresponsibility can cause burnout due to an overwhelming workload and the constant pressure to meet high standards.
  2. Perfectionism. When you are constantly not satisfied with your work and have to redo it every time, it causes a lot of stress. Unfortunately, our society is very sensitive to mistakes, and since school, you taught to be perfect.
  3. Not enough support and lack of results. Putting a lot of time, effort, and emotions into work without receiving positive emotional feedback, hearing criticism, and feeling that whatever you do is never enough can quickly make you overwhelmed and exhausted.
  4. Unregulated workload. When work takes up too much time and energy, it can be difficult to maintain a healthy work-life balance.

When cognitive load and stress come together, they can wear out mitochondria in neuron cells, which in turn affects their ability to recharge and perform optimally. This can lead to a decrease in cognitive abilities, mental fatigue, and an increased risk of burnout.


In conclusion, burnout is a major and serious issue affecting many people in high-paced environments. By understanding the biological mechanisms involved, such as the exhaustion of mitochondria in neuron cells, we can begin to address burnout as a legitimate health problem rather than simply dismissing it as tiredness.

The question is, does the number in the bank app worth people’s well-being? Maybe it’s time when more leaders to start looking toward the teal paradigm.



Demid Ost

Entrepreneur, investor, product manager, expat, rollerskater, geek, metalhead.